You’re working for a playground equipment company, which wants to know the rotational inertia of its swing with a child on board; the combined mass is 22 kg . You observe the child twirling around in the swing, twisting the ropes as shown in the figure. As a result, child and swing rise slightly, with the rise h in cm equal to the square of the number of full turns. When the child stops twisting, the swing begins torsional oscillations. You measure the period at 6.91 s . (Figure 1)
Figure1 of 1

Part A
What do you report for the rotational inertia of the child-swing system?